Find the wavelength of electromagnetic waves of frequency `4xx10^9Hz` in free space. Gives its two applications.

Find the wavelength of electromagnetic waves of frequency 4 x 10^9 Hz in free space. Give its two applications.

Find the wavelength of electromagnetic waves of frequency 6xx10^12Hz in free space. Gives its two applications.

Find the wavelength of electromagnetic waves of frequency 6xx10^12Hz in free space. Gives its two applications.

Find the wavelength of electromagnetic waves of frequency 5xx 10^(19) Hz in free space. Give its two applications.

Find the wavelength of electromagnetic waves of frequency 6 xx 10^12 Hz in free space. Give its two applications.